I have an Archer 6 router and 3 RE220 extenders in my home. I recently turned my detached garage in to a home office but the signal out there is really poor. I purchased a 4th RE220 and plugged that in there, but again, the signal is really poor. 

One RE220 in my home has an ethernet going out to a desktop computer and this works really well. I assumed the ethernet port was for sending signal from the extended to devices. However I'm now wondering if it works the other way?

If I were to cable an ethernet from my Archer A6 to the garage, could I plug this cable in to my RE220 to provide strong wifi output for the devices in and around the garage?

Apologies if my question isn't clear! Summary - can I use the ethernet port of RE220 to provide an RE220 with internet, rather than vice versa?

Thanks all :)